Problem: $\dfrac{18}{100} + \dfrac{17}{10} = {?}$
The fractions must have the same denominator before you can add them. Rewrite $\dfrac{17}{10}$ as $\dfrac{170}{100}$ $\dfrac{18}{100} + \dfrac{170}{100} = {?}$ $ = \dfrac{188}{100}$